This invention relates to the field of authorization cards, more particularly authorization cards for use as personal identity papers, value cards, credit cards, etc.
Authorization cards of this kind should not only be adapted for verification whether they are authentic and who is the owner of the card, but it should also be possible to check whether the actual user is the authorized owner of the card. In this way, the authorization card should be protected against unauthorized use by third persons.
Conventionally, automatic evaluation devices to which the authorization cards are presented are provided with a keyboard by which the user of the card may introduce a coded number which is compared with an information stored on the card. However, there is a risk that the introduction of the coded number is observed by third persons so that third persons may know the coded number.